Sandwich composite pipe

In recent years, there has been a tendency toward designing liners where the liner not only resists the internal pressure of the pipe but also the traffic and soil pressure. The latter assumes that at some point in the future the host pipe will fully disintegrate. While this may pose an extremely conservative view, it essentially requires building a new pipe inside the old pipe that could resist all internal and external loads independently of the host pipe. 

The design of such pipes is controlled by buckling of the liner (Moser and Folkman, 2008). The compressive strength of FRP products is lower than their tensile strength. 

Rehabilitation of Pipelines Using Fiber-reinforced Polymer (FRP) Composites 

A typical honeycomb pipe weighs 10—15% of a conventional hberglass pipe, and is signihcantly lighter when compared to a steel or concrete pipe. All of the aforementioned factors contribute to the low cost of this pipe. The sections of this pipe will be built in advance and will be used to slip-line the existing deteriorated steel pipe in the held. 

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Because the neutronics properties are major drawbacks for the use of these metals as cladding materials for Generation IV reactors, use of these materials as thin liners sandwiched with ceramic material composite (CMC), such as SiC/SiC composite, tubes was proposed [55]. In this system responsibilities of creep resistance, thermal stability, corrosion resistance, and gas tightness if necessary, are shared by the triplex layers as designed for CMC/steel composite pipes [56]. 

Processing Facilities. The phenolic-foam-producing process is simUar to that used with rigid polyurethane foams. Production of composite sandwich panels, board-type products, pipe covers, are possible. 

This chapter outlined varions applications of FRP in relation to pipes and risers, and those relevant to the petrochemical and oil and gas industries. It introduced various hybrid applications of FRP and its hybrid, such as the steel strip laminate pipe (SSLP) technology and the composite reinforced line pipe (CRLP) technology, and sandwich pipes as well as their pertinent design procedures. The issues affecting the long-term performance of these materials, as well as the issues involved in joining them, were also discussed. 

Rigid foams can be processed as continuous panels or by lamination between two surfacing materials (sandwich panels with a rigid polyurethane foam core). Composite sandwich panels may have particleboard or plasterboard on one surface and cement on the other. Foams can also be produced to fill cavities between metal sheets or sheets of reinforced plastics or in combination on either side. These structures are used as thermal insulation for refrigerator and freezer cabinets, refrigerated transportation vehicles, water heaters, pipes, pipe shells, tanks for gas storage or transport of liquified natural gas, and so on. 

Pipe can be coextruded with more than one layer, which results in a composite sandwich wall. Figure 10.4 shows a multimanifold die for extruding PVC or ABS pipe with three layers where the intermediate layer is a foam core. This results in a saving of weight the foam core pipe is 75-80% of the weight of solid pipe. Such pipe is used in city sewer applications. The ASTM standards for foam core pipe are F-268 for ABS and F891 for PVC. 

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